Requirement
The site studied was a very large facility undergoing reconversion that would result in it accommodating new consumption units and new generators (biomass plant) using the existing electrical grid. In this configuration, the operator, via a suitable structure, must ensure the supply of utilities (steam, electricity, etc.) for all of the industrial units present on the site. The realization of this service relies directly on the concepts of availability and reliability of the grids and the generators.
In this context, the project involved producing :
- An audit of the electrical grid consisting of identification of the strong and weak points of the HVA distribution network, in order to make the HVA grid reliable
- A complete review of the protection plan in light of the results from the dynamic study and the replacement of analogue protection relays by a new generation digital relays
Realization
Capsim used ETAP to model all of the grid on the site (i.e. nearly 300 HVA cells) so as to be able to calculate :
- the power flows (for 6 worst case configurations)
- the size-determining fault currents for the distribution equipment (for not more than 9 and not less than 5 worst case configurations)
CAPSIM was hence able to verify the sizing with respect to standards currently in force (cables, transformers, etc.) and, by analysis of the ground, to assess the degree to which the facilities were out of date.
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Selectivity curves from a transformer start-up
Results
The study was used to draw up a reliability action plan including the implementation of a new protection plan for the site and the replacement of certain outdated equipment. Moreover, the ETAP model is used to perform connection studies for the new production and consumption units on the site.
Diagram showing the selectivity principles used for a network area
